1. Field of the Invention
The present invention is directed to connection detection. More particularly, the present invention is directed to detecting whether two antennae are properly connected to a receiver, whereby more reliable reception of a broadcast can be ensured.
2. Background of the Invention
Satellite radio operators will soon provide digital quality radio broadcast services covering the entire continental United States. These services will offer approximately 100 channels, of which nearly 50 channels will provide music, with the remaining channels offering news, sports, talk and data.
Satellite radio has the ability to improve terrestrial radio's potential by offering better audio quality, greater coverage and fewer commercials. In October of 1997, the Federal Communications Commission (FCC) granted two national satellite radio broadcast licenses. The FCC allocated 25 megahertz (MHz) of the electromagnetic spectrum for satellite digital broadcasting, 12.5 MHz of which are now owned by Sirius Satellite Radio, New York, N.Y. and 12.5 MHz of which are now owned by XM Satellite Radio Inc., Washington, D.C.
In deploying satellite radio, one system plan calls for transmission of program content from two or more geosynchronous or geostationary satellites to both mobile and fixed receivers on the ground. In urban canyons and other high population density areas with limited line-of-sight (LOS) satellite coverage, terrestrial repeaters will broadcast the same program content in order to improve coverage reliability. Mobile receivers, in particular, will preferably be capable of simultaneously receiving signals from at least one satellite and one terrestrial repeater for combined spatial, frequency and time diversity, thereby providing significant mitigation of multipath interference and addressing reception issues associated with complete or intermittent blockage of the satellite signals. Further in accordance with this particular scheme, the 12.5 MHz band is split into 6 slots. In a preferred allocation of slots, four slots are used for satellite transmission and two slots are used for terrestrial reinforcement.
In view of the desirability to obtain the highest quality radio reception, especially in radios mounted in moving vehicles, two antennae are preferably employed to receive the broadcast radio signal: one antenna for the satellite signal and another antenna for the terrestrial signal. From a consumer point of view, however, it is important that there be a positive indication that both antennae are indeed connected to the radio receiver so that the consumer and radio broadcast service provider can be assured that the best reception is being obtained.